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.\" Written by: John H. Baldwin <jhb@FreeBSD.org>
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.Dd May 17, 2025
.Dt CLOSEFROM 2
.Os
.Sh NAME
.Nm closefrom ,
.Nm close_range
.Nd delete open file descriptors
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft void
.Fn closefrom "int lowfd"
.Ft int
.Fn close_range "u_int lowfd" "u_int highfd" "int flags"
.Sh DESCRIPTION
The
.Fn closefrom
system call deletes all open file descriptors greater than or equal to
.Fa lowfd
from the per-process object reference table.
Any errors encountered while closing file descriptors are ignored.
.Pp
The
.Fn close_range
system call deletes all open file descriptors between
.Fa lowfd
and
.Fa highfd
inclusive, clamped to the range of open file descriptors.
Any errors encountered while closing file descriptors are ignored.
Supported
.Fa flags :
.Bl -tag -width ".Dv CLOSE_RANGE_CLOEXEC"
.It Dv CLOSE_RANGE_CLOEXEC
Set the close-on-exec flag on descriptors in the range instead of closing them.
.It Dv CLOSE_RANGE_CLOFORK
Set the close-on-fork flag on descriptors in the range instead of closing them.
.El
.Sh RETURN VALUES
Upon successful completion,
.Fn close_range
returns a value
of 0.
Otherwise, a value of -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn close_range
system call
will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Fa highfd
argument is lower than the
.Fa lowfd
argument.
.It Bq Er EINVAL
An invalid flag was set.
.El
.Sh SEE ALSO
.Xr close 2
.Sh HISTORY
The
.Fn closefrom
function first appeared in
.Fx 8.0 .
.Pp
The
.Dv CLOSE_RANGE_CLOFORK
flag appeared in
.Fx 15.0 .
